Vitamin C Doses, Shellfish Don`t Mix

August 25, 1985|By Jon Van.

Eating shellfish and popping huge doses of vitamin C could prove lethal, say University of Illinois researchers who have made a surprising discovery about the nature of arsenic poisoning. The researchers in the university`s animal sciences department in Champaign found that forms of arsenic usually considered harmless can become strongly poisonous through an interaction with vitamin C. The unexpected finding by Gail Czarnecki, David Baker and John Garst concerns the way molecules of arsenic compounds are constructed. If atoms within the compounds share five electrons with neighboring atoms, they are said to be ``pentavalent`` and are fairly harmless. Several foods, especially shrimp and prawns, may contain high concentrations of such arsenic compounds. What the Illinois researchers found is that high doses of vitamin C convert the pentavalent compounds into trivalent arsenic, a highly toxic poison. Cysteine, a chemical sometimes given as a treatment for heavy metal poisoning, also converts arsenic to the trivalent, highly toxic form.

``Chronic exposure to arsenic is known to cause cancer in humans,`` said Baker. ``We now must wonder whether megadosing with vitamin C increases the risk of cancer by changing the form of arsenic in food.``

NEW TEST MEASURES INSULIN PRODUCTION

A new way of measuring with great accuracy human insulin production should help physicians treat diabetics with greater precision, researchers at the University of Chicago are hoping. ``One of the great difficulties in diabetes research up until now has been the lack of a good, reliable method of determining exactly how much insulin is being produced by the pancreas on a daily basis,`` said Dr. Kenneth Polonsky, one of the developers of the new test, which gauges insulin production by measuring a certain protein manufactured by the pancreas along with insulin. ``We are hoping that the information gained from this test will allow us to determine who really needs insulin injections and who can manage the disease through pills or dietary controls.`` Polonsky and colleagues have launched a study to determine the therapeutic value of the test. Diabetics between the ages of 35 and 65 who haven`t been treated or whose blood sugar hasn`t been controlled by treatment may call 947-1025 for information about the study. Overweight people who don`t have diabetes also will be studied.

MOSQUITOES DON`T SPREAD AIDS

The fear that the virus thought to cause AIDS could be spread by mosquitoes is groundless, Dr. D. Peter Drotman of the federal Centers for Disease Control writes in the Journal of the American Medical Association. AIDS, acquired immune deficiency syndrome, is known to be spread through intimate sexual contact and blood transfusions. ``The bulk of evidence argues against routes of transmission other than sexual or blood related,`` Drotman says. ``In other countries, such as Haiti or countries in Central Africa, heterosexual transmission seems to play a more important role than in North America or Western Europe,`` where most AIDS patients are homosexual. But insect-borne transmission has not been implicated in any country, and the low incidence of the disease in children argues against the insect-transmission theory, Drotman concludes.

ARGONNE`S ALEX AIDS METALS STUDY

Altering the pressure or temperature of a liquid can change its behavior as it flows, and when the liquid in question is a metal, variations in the magnetic field also become a significant factor. Because liquid metals likely will be used to cool fusion reactors of the future and to breed new fuel, understanding what affects their behavior is crucial to designing the generators intended to provide unlimited electrical power from elements found in seawater. To that end, researchers at Argonne National Laboratory have put ALEX to work. ALEX (Argonne Liquid Metal Engineering Experiment) is the world`s largest facility of its kind and is open to scientists throughout the world. It can produce magnetic fields up to 50,000 times stronger than the Earth`s normal field. Liquid metals will be passed through pipes of various sizes and geometric designs and changes in their behavior will be recorded.